An international team of astronomers has examined the low-mass X-ray binary system GX 339-4. The findings of the study, published on the pre-print server arXiv on November 21, provide further insights into the properties of this system and shed light on the high-frequency bump observed in the power density spectrum of GX 339-4.
X-ray binaries (XRBs) consist of a normal star or a white dwarf transferring mass onto a compact object, which can be a neutron star or a black hole. These binaries are categorized as either low-mass X-ray binaries (LMXBs) or high-mass X-ray binaries (HMXBs) based on the mass of the accompanying star.
GX 339-4, located approximately 39,000 light years away from Earth, is a recurrent black hole LMXB that was first detected in 1973. The black hole in GX 339-4 is estimated to be at least 5.8 times more massive than the sun. Over the past 30 years, GX 339-4 has experienced frequent outbursts, displayed quasi-periodic oscillations (QPOs), and exhibited all the black hole accretion states.
Overall, GX 339-4 has been extensively studied across various wavelengths, making it one of the most well-studied black hole LMXBs. Previous observations of this system have identified a high-frequency bump in its power density spectrum (PDS), which is believed to originate in the X-ray corona. This bump has a frequency exceeding 30 Hz and an rms of approximately 2-3%.
A team of astronomers, led by Yuexin Zhang from the University of Groningen in the Netherlands, decided to analyze archival data from the Rossi X-ray Timing Explorer (RXTE) spanning from 1996 to 2012 to investigate the nature of this high-frequency bump.
2023-11-30 03:41:03
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